1. Field of the Invention
The present invention relates to a wired circuit board, and particularly to a wired circuit board used preferably as a suspension board with circuit.
2. Description of the Related Art
A wired circuit board used for electronic/electric equipment or the like is typically formed with a terminal portion to be connected to an external terminal.
In recent years, to respond to the increase in the density of electronic/electric equipment and the reduction in the size thereof, a flying lead having a terminal portion formed not only on one surface of a conductive pattern, but also on each of the both surfaces of the conductive lead thereof has become prevalent. For example, it has been known that, in a suspension board with circuit used in a hard disk drive or the like, the both surfaces of a conductive lead are exposed to form a terminal portion as a flying lead. Such a terminal portion formed as a flying lead is bonded to an external terminal by, e.g., applying ultrasonic vibration thereto using an ultrasonic bonding device or the like.
The terminal portion formed as the flying lead is suited for bonding using ultrasonic vibration since the both surfaces of the conductive lead are exposed and an ultrasonic wave is readily transmitted thereto. However, the terminal portion formed as the flying lead has a problem in that the physical strength thereof is low and a stress is concentrated on an end portion of the terminal portion to easily cause a disconnection. To solve the problem, various suspension boards with circuits have been studied which allow the disconnection of the flying lead to be suppressed.
For example, a head suspension has been proposed in which a spring metal island is electrically and mechanically connected to a flying lead region where the both surfaces of a conductive lead are exposed to reinforce the conductive lead in the flying lead region (see, e.g., Published Japanese Translation of PCT Application No. 2007-537562).